No kidding, the counterbore bits and pilot system that Custom Fly Rod Crafters use everyday are the easier, quickest and most likely the safest cork grip inletting tools available. Everybody has struggled with putting the proper recess in the back of a cork grip to accept the hood of the uplocking reel seat. Everything from drill bits, to Dremel tools to reversed spade bits; none of these work as well as the counterbore and pilot system.
Since not every reel seat requires the same sized recess in the cork grip, we offer the counterbore bits in four diameters; 3/4", 25/32" (which by the way is the size required for a Lemke LC1 or LC10 reel seat), 13/64" and 7/8". The pilots are sized to fit the counterbores and come in three sizes; 1/4", 5/16" and 3/8", which are the three most common grip bore sizes. This HSS (high speed steel) counterbore bits were designed to go through metal which means that you probably will never dull one using them on cork. We use one of our lathes to make the recesses, but this system can easily be used with a drill motor, although we do recommend a drill stand just the keep everything steady.
Custom Fly Rod Crafters offer the counterbore system as single bits, $49.95 each, or you can purchase the set of four bits for $189.95.
The pilot set is sold a the set of three pilots, $23.95.
These images show how we do the simplest cork inletting:
